Apparatus for leveling piano keys



1623359 April 5, 1927. E. s RAUWORTH y v APPARATUS FOR LEVELIANG PIANO KEYS Filed July 28, 1923 Patented Aptav f 5, 1927.

niWi-NfISAMUELRAUWORTH; oFpEKALs liiiLiNois, Assieiiio'n To iioiliio'iifaio..

l CoM-Him?, oirDie,ifm-Lief ILLINOIS-,ALconPomiTioiioFiiLLiNois;

i preferably before installatinofthe piano "devices in conibinzition as ,herein sliotvn and described and 'as liid'ielited "by the lai'iis vgju're *1 is Va partial fiorit- 'eleva'itio'ii of a piano case with the keys mounted tlieij'ein invention positionedfforfuse.

,Figui-e2 iis detail section taken as in'- 'd'ijcgft'd yatline lon lligui'e 1;

'i Figure 3 is transverse secti'ontaken as indicated at line 3 3 on Figure l.

Each vot'ftlie keys, A, is retained l'it'i'ts'itulense-by an @standing posti Q1 pin',l B, ijf@- 'Vided'v'ith a felt-Washer oi'pad, l, and in seine' instances' With ,one or V'i'rore paper 'shfins,rz2.' Itis desirable, for fthe' sake of the technique 'of the; musician, that --ny j tliirnorniti'l 'position Ythe keys vs'liouldy Istand in alignment but this is not 'always die case after the. initial asseinbly. lFor correcting the 'alignment the number oi" l tliiclness, of the shinis, 2, applied to the'v ilciuii pin, B,

i v'must be'varied-and to' perhiit this it is neces sary to raise thekey aconsiderable'distance to 'the dotted ligne position indicated in Figure 3' atfA'. rl`his is not possible if the regiili"KV piano' action is already "iii position;

- theriore forthe piirposes'of the level-ing operation Il provide aduniiny'adtioii "designed to apply to the ini'ierfefnd of each 'key siibst'antiallyjthe saineiveight 'or prefs- 'sure' as it'Would :eiperiei'i'ce Yif lthe;``i`"e'g""ulai' action 'serein plaee f The d'uniriy jzictio'ii ctilisistsj :osupporting there are pivoted at 5 a. pluralitylof V'ii'feig'flrted ir's, 6', 'Wlii'ch may be `iliade of laminated f Wood.,l bored to carry' lnii'niber 'of' lead Weights, 7, as indicated-in' Figures-.2 and Y 3.' -The Weighted portion .of each of the arms, 6y carries a. contact button, 8, restingV upon Vone of the keys so that in the vnormal range of movement of the key it experiences at this point substantially the pressure which the regular action would pla-ce upon it. The arms, 6, however, are

Vfree to swing individually about their fulcrums at, 5, through a Wide range so as to permit raising the keys sufficiently to to resinas@iiifiiigrihesi and Y chosen to" represent Vtlie iioiiii es. @een si. eine.'

@mower sp'piythe ssii-n1 wisse-s, 2, seine -fiil'crti'ii'i pins, B. 'their frfwtidiedge's sies-arms,egale formeuwithfgeis pf ses, f

iduillyfi-*ii withdrawing' or' iepieing my sing-m1 key which may require special fitting. fl-lie Ciiimfyaeifioii is, iimiiy nei-ci in #pues auf ing Athe testing and adjusting" of the keys Y Y 'engage regs, 3, the bra-dicte, and es si ftiieiffespesiie @ses sie steed wiiii- Ciani 'the key frame. y

is Cesjunetion wishful@'tisiiiiyesseri .K

empioy la masseuse-g"instrument in 'the T ii, iviiieiiis messed se misre@ 'the eerily end of the rod, (19, Whose uppffei'ld is threaded and provided with ari-'adjusting rei seeing its iii-siiiA position with? rasees@ t i se sfeer tiv'e: I'iositfionv Beginning" Vati-fone"end "of-the 5 keybeme the @Offresi essersi@ @fragile gnge with issuing se of variance of the readingA from the nori'ial Ito to insert; the selected shims at the fulcrum forthis purpose. Y Y

" Then the process 1s applied to the black*V keys.vr ff W 'Byy providing shims of several thicknesses andif' necessary furnishingv special thin or pins,.B, lifting the keys to the position, A1,

f thick pads, 1, it becomes a simple matter for vthe workman to determine from'the first auge reading Yjust what shims he Yshould add'jto bring the key to a normal level. If

l fthe keys are all assembled .without any shims but `merely with the pads, 1, in iplace,

fa' normal lev'eljmay be chosen which will require at least'one shim washer, 2, in .pracf tically every case.-

' lAnother,'appl'cation of Vthe apparatus' is fonsecuring afuniformy depressionv for the "-keys;. this dimension V1s determined by the ,depth 0f paesana, Shims, 11L and 2, YGSPGC* tivelyfwhichare applied tothe post or pin,

.Dylocated*underithe 'forward end .of each key and projecting into a recess, E, therein 1 when the keyisdepressed.` A definite gauge reading yis chosen to'correspond to the de- Vsiredposition ofthe key at full depression hand by'. depressing each key and applying :the gauge the workman isyenabledto judge just whatthickness of shims, 2a, to add toV thepad, 1,{for` arresting the key movement at this predetermined limit. Preferably the ".sliims are applied Vunder the pads so thaty the felt pad maybe left uppermost to. keep the i `igkeyaction as quiet aspossible. As in levelving the'keys at normal position two settingsY of the rgauge will be required in .adjusting v.the depression,.-.one se-tting for the white V.vertically movable member whichV maybe j lowered at will linto contact with thekeys,

Y `.one Vat va time, Vand, includingan indicator operableby the movable member for show- .ingthepositionof the latter withreference .vtoa'predetermined normal.. j Y n @52".QIn the apparatus defined by claim 1,

la] carriagev .supporting said gauge on said rail and provided with means for raising and lowering the gauge bodily on the guide Hill. Le., v v i l v 3. In combination with a guide rail provided with standards for supporting it over the keys of a piano, and a gauge device slidably mounted on said rail and having a member adapted -to "depend for engagement with the piano keys, one at a time, a dummy action comprising ya series of arms and a support upon which they. are fulcrumed in position to rest upon the respective keys of the piano, to impose a loadv thereon in lieu l of the weight of the pianol action, said arms being mounted to swing freely upward to permit raising the keys suiiiciently toclear their fulcrum pins. *y h Y Y 4. In the combination defined in claim 3, said arms .being individually pivoted to swing about their fulcrums independently of each other, and means extending from each armto serve as a handle for so swinging it. i f

5. In the combination defined in clainr, said rarms being individually pivotedV to swing about their fulcrums independently of each other, andaforwardly exposed inger piece on each thearm. y .j

V6. In the apparatusdefined in claim 1,V a carriage kon the guide railand a casing for the depth gauge vertically movable on said yarm to facilitate lifting carriage with a stop for. limiting the downward movement of the casing; the said member which contacts with Vthe keys being vertically movable with respect to the casing independently of the movement of the latter on the carriage whereby said member may .be arrested by its contact with the keys in-` dependently of the stop which limits the lowering of the casing.

' 7.7V In the apparatus carriage ontheguide rail and a casing for ithe depth gauge', vertically movable on said carriage, with a stop for limiting the do-wntically4 ymovable with respect to the casing,

Aso

defined ia nim i, f

V.ward movementof the casing; the said meml ber which contacts with the keys beingv very Y independently 'of the movement of the latter on the carriage, whereby said member may Vbe arrested by its contact with the keys independently of the stop which` limits the lowering of the casing; and meansv for ad#` just-ingy said. stop vertically4 for setting the predetermined normal. Y

In testimony whereof, I have hereunto Vvset` my handvat De Kalb, Illinois.

EDWIN SAMUEL aMiwoirrrr.1` j 

